Muffler having a cover and a retaining strip therefor



May 13, 1958 w. H. POWERS ET AL 2,334,427

MUFFLER HAVING A COVER AND A RETAINING STRIP THEREFOR Filed Dec. 22. 1953 2 Shets-Sheet 1 i 1 INVENTORS:

' hflif /9, %wers BY .Zevzorr J 126 z I 2 Sheets-Sheet 2 May 13, 1958 w. H. POWERS ET AL MUFFLER HAVING A COVER AND A RETAINING STRIP THEREFOR Filed Dec. 22, 1953 MUFFLER HAVING A covER AND A RETAINING STRIP THEREFOR Walter H. Powers and Benton Jacokes, Jackson, Mich.,

assignors to Walker Manufacturing Company of Wisconsin, Racine, Wis., a corporation of Wisconsin Application December 22, 1953, Serial No. 399,686

2 Claims. (Cl. 181-61) This invention relates to mufflers and, more particularly, to a novel cover for mufflers of the type adapted to silence the exhaust gases of internal combustion engines and the like.

In the past, the usual methods for manufacturing a mufiler having a non-heat conducting material wrapped around the outer shell have ordinarily involved the use of spot welding or lockseaming to secure a metal cover over the non-heat conducting material. It is an object of this invention to provide an improved muffler having a non-heat conducting material wrapped around the outer shell thereof and secured thereto by means of a novel metal cover and retaining strip.

It is another object of this invention to provide a novel metal cover and retaining strip, adapted to secure a nonheat conducting material to the outer surface of a mufiier shell, which is simple and rugged in construction and relatively inexpensive to manufacture.

Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

Figure 1 is a perspective view of a mutfier constructed in accordance with the principles of the invention;

Fig. 2 is a central vertical longitudinal section through the mufller of Fig. 1;

Fig. 3 is an enlarged sectional view of the structure illustrated in Fig. 2, taken within the circle marked 3;

Fig. 4 is a vertical sectional view of the structure illustrated in Fig. 2 taken along the line 44 thereof, showing the mufiier cover locked along the side of the muffler;

Fig. 5 is an enlarged sectional view of the structure illustrated in Fig. 4, taken within the circle marked 5;

Fig. 6 is an end view of the locking strip for a muffler cover made in accordance with the principles of the invention;

Fig. 7 is a fragmentary view of a modification of the structure illustrated in Fig. 4 showing the mufller cover locked along the top of the mufiler; and

Fig. 8 is a fragmentary view of a modification of the structure illustrated in Fig. 4 showing the cover locked in a position between the side and top of the mufiier.

Referring now to the drawings in detail, a conventional straight-through flow resonator type mufiler is illustrated which has a double wrapped metal shell 10 secured to the end headers 12 and 14 in overlapped, rolled-together joints 16. The muffier has a straightthrough, perforate gas conduit 18 with inlet and outlet ports or bushings 20 and 22 fastened to headers 12 and 14. An inner shell 24 surrounds conduit 18 and is divided by partitions 26 into tuning chambers. Partitions 26 serve to support conduit 18 in shell 24 and partitions 28 support shell 24 and conduit 18 in shell 10 and also to divide the casing into a series of resonator chambers communicating with the conduit 18. Since operation of the muffler is obvious to those in the art, it will not be described.

United States Patent 0 2,834,427 Patented May 13, 1958 ice A layer of non-heat conducting material 30, such as asbestos, is wrapped around the outer surface of the shell 10 and is retained thereon by a sheet metal cover 32. As is best seen in l, the cover 32 comprises a substantially rectangular piece of sheet metal which is wrapped around the outer surface of the non-heat conducting material 30. The adjoining longitudinal ends of the cover 32. are bent backwardly to form a pair of longitudinally extending ears 34 and 36 which extend outwardly in opposite directions. A sheet metal retaining strip 38 bent along its longitudinal center line to form a pair of downwardly slanting shoulders 40 and 42 (Fig. 6) and having the longitudinal edges thereof folded downwardly and inwardly to form a pair of inwardly facing channels 44 and 46, is adapted to be slid endwise over the longitudinal cars 34 and 36 to form a rigid cover joint. The distance between the inner surfaces 48 and 50 of the channels 44 and 46 respectively is less than the distance between the outer surfaces 52 and 54 of the ears 34 and 36 respectively, so that when the retaining strip 38 engages said ears, an inwardly directed force will be exerted on said ears to draw the cover 32 snugly against the non-heat conducting material 30 to hold said material securely in place on the outer surface of the shell 10. The shoulders 40 and 42 of the retaining strip 38 may be flexed upwardly to increase the distance between the surfaces 48 and 50,

if necessary, to start said strip on the ears 34 and'36. As is best seen in Figs. 4, 7 and 8, the metal cover 32 may be disposed on the mufiler so as to have the longitudinal joint, formed by the ears 34, 36 and the retaining strip 38, positioned on the side, top, or any other desirable location. I

Use of the locking channel 38 and retaining shell 32 provides a simple, inexpensive means to secure the asbestos layer 30 in place. The extra thickness provided by shell 32 and asbestos 30 increases the insulation and easing strength of the muffler and permits some reduction in thickness of metal used in shell 10 and an overall improvement in the product at a minimum of cost.

It will be appreciated that although the novel sheet metal cover 32 is illustrated on a mufiier of oval cross section, it may also be adapted for use on mufflers of other cross sectional shapes, as for example, a circular muffler. It can, obviously, be used in many other types of mufflers.

While it will be apparent that the preferred embodiments of the invention herein disclosed are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. A muffier for silencing exhaust gases comprising, a casing having a gas inlet port and a gas outlet port, means between said ports in said casing adapted to silence exhaust gases, a layer of non-heat conducting material on the outside surface of said casing, a sheet metal cover wrapped around said casing and adapted to hold said non-heat conducting material in place, said cover having its adjoining longitudinal edges folded upwardly and backwardly to form a pair of outwardly extending longitudinal ears, a sheet metal retaining strip bent along its longitudinal center line to form a pair of downwardly slanting shoulders flexible about said center line, said shoulders having the longitudinal edges thereof folded downwardly and inwardly to form a pair of inwardly facing channels adapted to be slid over said outwardly extending longitudinal ears to lock said cover on said casing.

2. In a muffler having a sheet metal cover wrapped around the outside thereof, said cover having its adjoining longitudinal edges folded backwardly to form a pair of outwardly extending longitudinal ears, a sheet metal retaining strip bent along its longitudinal center line to form a pair of downwardly slanting shoulders, said shoulders having the longitudinal edges thereof folded downwardly and inwardly to form a pair of inwardly facing channels, the distance between the inner surfaces of said channels being less than the distance between the outer surfaces of said ears, whereby when said retaining strip is slid longitudinally over said outwardly extending ears, said inwardly facing channels wiil enclose said ears and exert an inwardly directed clamping force thereon to form a rigid joint therebetween.

References Cited in the file of this patent UNITED STATES PATENTS Hamilton July 16, Hunt Aug. 3, Bisplinghoff Mar. 9, Warsing Mar. 14, Curry Nov. 7, Moss Mar. 24,

FOREIGN PATENTS Great Britain Oct. 23, Great Britain Mar. 21, 

